Technical Field
The disclosure is related to an array substrate having a touch function and a display device.
Related Art
ITO (indium tin oxide, a transparent conductive material) is adopted to manufacture a rectangular array of electrodes arranged regularly (touch sensor) on the surface of a glass substrate. These horizontal and vertical electrodes, respectively, constitute a capacitor with the ground, which is commonly referred as a self-capacitance touch screen. A planar structure of a common self-capacitance touch screen is shown as FIG. 1. The self-capacitance touch screen comprises a plurality of array unit 1. Each array unit 1 respectively corresponds to an ITO touch electrode. Each ITO touch electrode connects to the touch circuit 3 through a metal line 2 to achieve touch operation. When a finger touches the capacitor screen, the capacitance of the finger will be superimposed onto they capacitance of the screen body such that the capacitance of the screen body increase. When the touch is inspected, the horizontal and vertical electrodes on the self-capacitance touch screen are sequentially inspected. The horizontal coordinate and the vertical coordinate are respectively determined according to the capacitance variation before and after the touch. A planar touch coordinate is then generated to finally locate the precise position of the touch.
However, due to the existence of the conductive scan lines and the data lines, it is easy to form parasitic capacitance between these conductive lines and the touch electrodes. This parasitic capacitance is easy to interfere with the sensing capacitance during the touch sensing such that the sense accuracy declines. If the total capacitance is referred as Cp when the screen is not touched, and the capacitance between the finger and the ground is referred as Cf when the screen is touched, the touch accuracy is Cf/(Cp+Cf) % (Formula I). The existence of the parasitic capacitance between the touch electrode and the data line results in the increase of Cp. From the calculation of Formula, the occurrence of the parasitic capacitance greatly reduces the touch accuracy of the touch screen.